While the $100 bill issued by the United States is a favorite, by far the worst offender is the European Union's 500 euro note, which is worth a whopping $556 USD.

"[I]n certain circles the 500 euro note is known as the 'Bin Laden,'" Summers points out.

"[I]llicit activities are facilitated when a million dollars weighs 2.2 pounds as with the 500 euro note rather than more than 50 pounds as would be the case if the $20 bill was the high denomination note."

Summers went on to say that the bills bearing the faces of Benjamin Franklin and President Ulysses S. Grant (the $50 bill) have their share of the blame, too.

Speaking about steps Western governments could take, Summer said that "the most important actor by far is the European Union. The €500 is almost six times as valuable as the $100 . . . If Europe moved, pressure could likely be brought on others, notably Switzerland."

The Wall Street Journal's MarketWatch reported that some of the biggest U.S. bills ever produced — including the $500, $1,000, $5,000, and $10,000 notes — were phased out in 1969. Up until that point, they were mostly used by banks, and today many collectors seek them.